Embodiments of the inventive concepts described herein relate to semiconductor memory devices, and more particularly, to resistive memory devices that have a separate sensing circuits and to related methods of sensing data.
Semiconductor memory devices are classified into volatile memory devices and nonvolatile memory devices.
Volatile memory devices, such as SRAM, DRAM, SDRAM, etc., lose data stored therein at power-off, while nonvolatile memory devices retain data stored therein even at power-off. Example nonvolatile memory devices include a Read Only Memory (ROM), a Programmable ROM (PROM), an Electrically Programmable ROM (EPROM), an Electrically Erasable and Programmable ROM (EEPROM), a flash memory device, a Phase-change RAM (PRAM), a Magnetic RAM (MRAM), a Resistive RAM (ReRAM), a Ferroelectric RAM (FRAM), etc.
Various of the nonvolatile memory devices, including the MRAM, PRAM, and ReREM memory devices, may store data based on a resistance state of each memory cell. For this reason, such nonvolatile memory devices may be called “resistance memory” devices. A sensing margin of a sensing circuit may take on increased importance when a ratio of high resistance to low resistance is reduced.